Features Include:
Complies to r/agario no cheating rules
Use custom skins that are seen by other script users
Show mass on player is selected on start up
Touchpad fix to prevent accidental freezing
Includes popup confirming intent to leave agario
Mass-graph to show your performance
End-of-game statistics
Checkbox settings are now savedNEW Press ALT+1 for FPS counterNEW Press Z for statsNEW Press T for Time benchmarkNEW Firefox fullscreen mode with Ctrl-fNEW Sound effects
NEW Background music
NEW Acid Mode
NEW Volume settings, graph toggle, etc.

To run this script you require greasemonkey installed in your browser first.

Agariomods

More skins

Iomods has a large directory of skins that can be used by setting your name to the skin name. This list can be found at skins.iomods.com

Connect skins

Connect is a service where you create an account, upload a skin, which you can then use in-game by setting your name to *Username. The * is needed at the start.

Client skin

This feature allows you to enter a url of an image to use as your skin. Note that this skin will only be seen by you, so it's mostly only useful for recording.

Themes

Themes are mainly a selection of backgrounds, and they're are very few of them at the moment. Themes can also have experimental animated skins for viruses and/or food.

Custom background

This is the last option in the Themes setting. This will let you enter a url of an image to be used as the game's background.

Sound effects

Sound effects play when you eat things, there's a sound effect for eating pellets, cells, viruses, as well as spawning and dying.

Background music

Background music plays in the background when you load up agar.io. There's a variety of tracks in the shuffled playlist. The tracks are chiptune from creators at battleofthebits.org, all royalty free. No copyright issues with recording with music playing.

Team mass

When you have the "Show Mass" setting enabled, while playing in the teams gamemode, you will be able to see the mass of cells on your team.

Advanced settings

You can access advanced settings by clicking the wrench icon in the top-right of the right panel.

Debug info

Enables through advanced settings. Shows native debug stats, which is normally accessed through http://agar.io/?debug this shows a graph of your FPS and network connection.

FPS counter

Simple little fps counter in the top-left corner of the screen, if you dont need the entire debug menu.

Disable lag popup

Agario may make a subtle popup at the bottom of the screen if you are experiencing latency issues. As per request of a recorder, I made an advanced setting to remove it.

Leave page confirmation

While you are in-game, if you try to navigate away from the page, the mod will ask ror confirmation.

Slitheriomods

Skins

This allows you to use Agariomods and Connect skins in slither. This replaces your snake's head with the selected skin, and removes the eyes for better skin visibility, which can be seen by others.

Backgrounds

This replaces the background with a random background of the selected theme.

Zoom

You can zoom in and out witht the scroll wheel to get a better view of your surroundings. This feature is arguably "cheaty", but for now, it doesn't seem to be hurting anyone's gameplay experience. If it becomes a problem, It'll be removed.

Party system

This is recreates the functionality of agario parties. You generate a party token, which can be used to join the server you are playing on.

Leave page confirmation

While you are in-game, if you try to navigate away from the page, the mod will ask ror confirmation.

Custom background

This is the last option in the Themes setting. This will let you enter a url of an image to be used as the game's background.

Sound effects

Sound effects play when you eat things, there's a sound effect for eating pellets, cells, viruses, as well as spawning and dying.

Background music

Background music plays in the background when you load up slither.io. There's a variety of tracks in the shuffled playlist. The tracks are chiptune from creators at battleofthebits.org, all royalty free. No copyright issues with recording with music playing.